Department of Horticulture Science, College of Agriculture and Natural Resources, University of Tehran, Karaj, 31587, Iran.
Biol Res. 2021 Jan 6;54(1):1. doi: 10.1186/s40659-020-00325-z.
Apple is one of the oldest and most valuable fruits. Water restriction is one of the major problems in the production of this fruit in some planting areas.
Effects of kaolin spray treatments were studied on two early apple cultivars of Golab and Shafi-Abadi under sustained deficit irrigation (SDI) in Alborz province, Iran during 2017 and 2018. Irrigation treatments were 100%, 85%, and 70% ETc and kaolin application were concentrations of 0, 3 and 6% in 2017 and 0, 1.5 and 3% in 2018.
Results showed that 85% ETc treatment compared to other irrigation treatments improved apple tree crown volume in 2017. Deficit irrigation treatments significantly reduced fruit weight in both years. Application with 6% kaolin resulted in 33.3% increase in apple fruit weight compared to non-kaolin treatment at 100% ETc irrigation in the first year. Severe deficit irrigation (70% ETc) significantly reduced apple fruit length in both years, but 6% kaolin increased fruit length in both apple cultivars in 2017. Severe deficit irrigation treatment increased the firmness of apple fruit compared to control and mild deficit irrigation (85% ETc) in the first year of experiment. There was no significant difference between irrigation treatments for apple fruit firmness in the second year of experiment. Kaolin treatments of 1.5% and 3% at full irrigation increased the soluble solids content of apple fruit by 36.6% and 44.1% in 2018, respectively. Deficit irrigation treatments significantly increased leaf proline content compared to control in both years. In the first year, kaolin treatments increased leaf proline but in the second year, leaf proline was not significant. Deficit irrigation treatment of 70% ETc and 6% kaolin had the highest amount of glycine betaine content, malondialdehyde and hydrogen peroxide in apple leaf in the first year of experiment.
Severe deficit irrigation stress (70% ETc) increased the activity of nonenzymatic defense systems of apple trees. Kaolin as a drought stress reducing agent can be recommended in apple orchards of Golab and Shafi-Abadi cultivars as an effective and inexpensive method to improve tolerance to drought stress conditions.
苹果是最古老、最有价值的水果之一。在一些种植地区，水资源限制是苹果生产的主要问题之一。
本研究于 2017 年和 2018 年在伊朗阿尔博兹省，针对两个早熟苹果品种 Golab 和 Shafi-Abadi，研究了在持续亏缺灌溉（SDI）下施用高岭土喷雾处理的效果。灌溉处理分别为 100%、85%和 70%ETc，高岭土施用量为 2017 年 0、3 和 6%和 2018 年 0、1.5 和 3%。
结果表明，与其他灌溉处理相比，2017 年 85%ETc 处理可提高苹果树冠体积。在这两年中，亏缺灌溉处理均显著降低了果实重量。与 100%ETc 灌溉下的非高岭土处理相比，第一年施用 6%高岭土可使苹果果实重量增加 33.3%。在这两年中，严重亏缺灌溉（70%ETc）均显著降低了苹果果实的长度，但 2017 年 6%高岭土处理增加了两个苹果品种的果实长度。与对照和轻度亏缺灌溉（85%ETc）相比，第一年试验中严重亏缺灌溉处理提高了苹果果实的硬度。第二年试验中，灌溉处理对苹果果实硬度没有显著影响。在充分灌溉条件下，1.5%和 3%的高岭土处理分别使苹果果实的可溶性固形物含量增加了 36.6%和 44.1%。在这两年中，与对照相比，亏缺灌溉处理均显著增加了叶片脯氨酸含量。在第一年，高岭土处理增加了叶片脯氨酸含量，但在第二年，叶片脯氨酸含量没有显著差异。与对照相比，第一年试验中，70%ETc 亏缺灌溉和 6%高岭土处理使苹果叶片中的甘氨酸甜菜碱、丙二醛和过氧化氢含量最高。
严重亏缺灌溉胁迫（70%ETc）增加了苹果树非酶防御系统的活性。高岭土作为一种抗旱胁迫缓解剂，可作为提高 Golab 和 Shafi-Abadi 品种苹果对干旱胁迫条件耐受性的有效且廉价的方法。
